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Welding stray earths

Posted: Wed Nov 02, 2016 10:43 pm
by skippy
Has anybody ever had an electrical component destroyed while welding?
I can't see how it can happen unless the component is permanently connected and running at the time. I disconnect the battery earth just in case but on our bikes with power switched off where is a cct available for stray power?

Re: Welding stray earths

Posted: Thu Nov 03, 2016 2:42 pm
by Mark Cook
I think it's a bit like crossing the road with your eyes shut.
Is it worth the risk? Just make sure the welding return is close to where you are welding.

Note the expression "welding return" could be positive, negative or AC. Might even have a HF component.

Just for the smart so and so's, not a problem with gas welding or brazing.

Re: Welding stray earths

Posted: Thu Nov 03, 2016 5:10 pm
by Andy Chaos
On one of the scrapheap challenge shows we did years ago someone did some welding to vehicle with 2 x 200hp outboard motors hanging off the back.When it came to starting them back up only one would run, the other had lost its spark and needed a new cdi unit.
Not worth the risk but might be one for the mythbuster to prove.

Re: Welding stray earths

Posted: Fri Nov 04, 2016 2:33 am
by HPbyStan
Image
When welding on the Astro-mino I forgot to disconnect the battery one time and melted several wires together where I couldn't get at them to fix and had to rerun wires a different way. I hate it when it's my fault.

Re: Welding stray earths

Posted: Wed Nov 09, 2016 4:12 pm
by stew79
i have carried out tig welding on several of my old cars vans and bikes for many years, i have never disconnected any thing. to just disconnect the battery, but leave every thing else joined up and still earthed (including the ignition) seems not to have any logic.(you would have to completely disconnect every single thing thats earthed to the metal of the vehicle?) hpbystan, when you did your welding on your truck, you must have accidental melted through some wires perhaps behind a panel, or near were you were welding. its the only way for a current to flow through the truck wiring to cause the problem. (it may have still happened with the battery disconnected, but you only would have found out about the short circuit when you went to re connect the battery.)
stew

Re: Welding stray earths

Posted: Thu Nov 10, 2016 8:29 pm
by HPbyStan
Man, I gotta quit posting on here.

Re: Welding stray earths

Posted: Thu Nov 10, 2016 10:34 pm
by minetymenace
:shock:
Just say the word Stan.